// This file is part of www.nand2tetris.org
// and the book "The Elements of Computing Systems"
// by Nisan and Schocken, MIT Press.
// File name: projects/04/Fill.asm

// Runs an infinite loop that listens to the keyboard input.
// When a key is pressed (any key), the program blackens the screen,
// i.e. writes "black" in every pixel;
// the screen should remain fully black as long as the key is pressed. 
// When no key is pressed, the program clears the screen, i.e. writes
// "white" in every pixel;
// the screen should remain fully clear as long as no key is pressed.

// Put your code here.

@8192
D=A
@dm
M=D

(MAIN)
    @SCREEN
    D=A
    @cur
    M=D

    @KBD
    D=M

    (SETMINUSONE)
        @SETMINUSONEEND
        D;JLE
        D=-1
    (SETMINUSONEEND)

    @curcolor
    M=D 

    @now
    M=0

    @PAINT
    0;JMP

(PAINT)
    @dm
    D=M
    @now
    D=D-M
    @MAIN
    D;JLE

    @curcolor
    D=M
    @cur
    A=M
    M=D

    @now
    M=M+1
    @cur
    M=M+1

    @PAINT
    0;JMP
